The development of the Internet over the last years has made it possible to connect various types of electrical devices to one another. Notable examples of such electrical devices are personal computers and information portable terminals. The information exchanged between such devices is commonly video information, such as characters and images, and audio information. Further, as the broadband network connection becomes more popular, the always-on connections are taking over the dial-up connections as a means to access the Internet.
One form of Internet connection that has been getting attention recently is a power line communications system, which uses the power lines of homes and other places as an interface. In such a power line communications system, the power line used to supply power to the electrical device is used to make an Internet connection. An example of such a technique is disclosed in Japanese Publication for Unexamined Patent Application No. 275102/1999 (Tokukaihei 11-275102, published on Oct. 8, 1999). Another example is found in Japanese Publication for Unexamined Patent Application No. 27577/2002 (published on Jan. 25, 2002), which discloses making Internet connections via telephone lines by controlling a power supply to electrical devices.
Further, the wide-spread use of the Internet have brought a variety of Internet-connectable devices, which include not only information processing devices such as personal computers and information portable terminals but also other types of devices such as a microwave that can download a recipe via the Internet, for example.